Dynamic spinal stabilization assemblies, tool set and method

ABSTRACT

A hinged bone screw and tool set is used for implanting such bone screws in a human spine, followed by the implantation of a longitudinal connecting member into the bone screws. The hinged bone screw includes a shank with an upper portion and a receiver with integral arms forming a U-shaped channel. A lower curved seat partially defining the U-shaped channel cooperates with an upper portion of the bone screw shank for hinged movement of the shank with respect to the receiver. The tool set includes an insertion tool, a bone screw driver, a reduction tool and a closure starter. The insertion tool includes a bone screw attachment structure and a laterally opening channel. The insertion tool further includes a threaded portion for cooperation with the reduction tool to provide synchronized placement of a closure structure in the bone screw receiver while reducing and capturing a longitudinal connecting member within the receiver. Further alternative bone screws are hinged, polyaxial or fixed and include lordosing or kyphosing lateral surfaces.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.14/482,562, filed Sep. 10, 2014. U.S. patent application Ser. No.14/482,562 is a divisional of U.S. patent application Ser. No.12/927,673, filed Nov. 19, 2010, which issued as a U.S. Pat. No.9,216,039 on Dec. 22, 2015, and is a continuation of U.S. patentapplication Ser. No. 11/328,481, filed Jan. 9, 2006, which issued asU.S. Pat. No. 7,862,587 on Jan. 4, 2011, which claims the benefit of thefiling date of U.S. Provisional Application, No. 60/722,300, filed Sep.30, 2005; No. 60/725,445, filed Oct. 11, 2005; No. 60/728,912, filedOct. 21, 2005 and No. 60/736,112, filed Nov. 10, 2005, all of which areincorporated herein by reference. U.S. patent application Ser. No.11/328,481 is a continuation-in-part of U.S. patent application Ser. No.11/272,508 filed Nov. 10, 2005, which issued as U.S. Pat. No. 9,050,148on Jun. 9, 2015, and claims the benefit of U.S. Provisional ApplicationNo. 60/630,536 filed Nov. 23, 2004; and is a continuation-in-part ofU.S. patent application Ser. No. 10/996,289 filed Nov. 23, 2004, whichissued as U.S. Pat. No. 8,152,810 on Apr. 10, 2012; and also is acontinuation-in-part of U.S. patent application Ser. No. 10/789,149,filed Feb. 27, 2004, which issued as U.S. Pat. No. 7,160,300 on Jan. 9,2007; all of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to apparatuses and methods for use inperforming spinal surgery and, in particular, to bone attachmentstructures, bone attachment insertion and manipulation tools and methodsof using such tools, especially for percutaneously implanting spinalscrews and for implanting a dynamic stabilization connecting member forspinal support and alignment, using minimally or less invasivetechniques.

For many years, spinal osteosynthesis apparatuses have been utilized tocorrect spinal deformities, injuries or disease. In such procedures,substantially rigid longitudinal connecting members, for example,elongate solid rods, are surgically attached to vertebrae of the spineto provide support and/or to realign or reposition certain vertebrae.The longitudinal connecting members are typically secured to vertebraeutilizing bone screws and other spinal implants. In order to reduce theimpact of such surgery on the patient, a desirable approach is to insertsuch implants percutaneously or with surgical techniques that are lessinvasive to the body of the patient. In order to provide for protectedmotion with more normal or natural spinal flexibility, more flexible ordynamic longitudinal connecting members may be chosen over solid rigidrods.

Problems arise when implant deployment and insertion tools designed fortraditional open surgery that is more invasive are utilized inpercutaneous or less invasive surgery or with dynamic stabilizationlongitudinal connecting members. The tools may be bulky, oversized orhave irregular surfaces or protrusions that can catch and traumatizetissues. A projecting actuator arm or fastening member may be usefulwith respect to the spinal screw implantation process or the rodreduction process, but there may be insufficient clearance to use suchstructure and/or such structure may produce additional unwanted traumawhich the percutaneous surgery is attempting to avoid.

A percutaneous or less invasive procedure also presents a problem withimplantation of elongate connecting members that have historicallyrequired a long incision and open wound in order to provide for thelength of the connecting member and the space required for the surgeon'shands as well as the tools needed to manipulate the rod. Such problemsare then compounded by the implants and insertion tools used with theconnecting member.

Consequently, it is desirable to develop apparatuses and techniques thatallow for the insertion of bone screws, the insertion and reduction ofelongate connecting members into the bone screws and the securing of theconnecting member to the bone screws with significantly less invasioninto the body of the patient.

Historically, it also has been common to fuse adjacent vertebrae thatare placed in fixed relation by the installation therealong of bonescrews or other bone anchors and cooperating longitudinal connectingmembers or other elongate members. Fusion results in the permanentimmobilization of one or more of the intervertebral joints. Because theanchoring of bone screws, hooks and other types of anchors directly to avertebra can result in significant forces being placed on the vertebra,and such forces may ultimately result in the loosening of the bone screwor other anchor from the vertebra, fusion allows for the growth anddevelopment of a bone counterpart to the longitudinal connecting memberthat can maintain the spine in the desired position even if the implantsultimately fail or are removed. Because fusion has been a desiredcomponent of spinal stabilization procedures, longitudinal connectingmembers have been designed that are of a material, size and shape tolargely resist bending (flexion, extension and sideways), twisting(torsion), compression and distraction, and thus substantiallyimmobilize the portion of the spine that is to be fused. Thus,longitudinal connecting members are typically uniform along an entirelength thereof, and usually made from a single or integral piece ofmaterial having a uniform diameter or width of a size to providesubstantially rigid support.

Fusion, however, has some undesirable side effects. One apparent sideeffect is the immobilization of a portion of the spine. Furthermore,although fusion may result in a strengthened portion of the spine, italso has been linked to more rapid degeneration and even hyper-mobilityand collapse of spinal motion segments that are adjacent to the portionof the spine being fused, reducing or eliminating the ability of suchspinal joints to move in a more normal relation to one another. Incertain instances, fusion has also failed to provide pain relief.

An alternative to fusion and the use of more rigid longitudinalconnecting members or other rigid structure has been a “soft” or“dynamic” stabilization approach in which more elastic materials and/orshapes are utilized for a longitudinal connecting member fixed between apair of pedicle screws in an attempt to create, as much as possible, amore normal loading pattern between the vertebrae in flexion, extension,compression, distraction, side bending and torsion. Tools utilized withtraditional rods or other more rigid structure may not be appropriatefor manipulating more flexible connecting members and cooperating boneattachment structures. The dynamic conditions associated with spinalmovement therefore provide a challenge not only for the design ofelongate elastic longitudinal connecting members, but also for thedesign of cooperating bone attachment structure and tooling.

SUMMARY OF THE INVENTION

Bone attachment assemblies and cooperating tools for manipulating suchassemblies according to the invention are provided for use in minimal orless invasive surgery, including dynamic spinal stabilization. Anillustrated bone attachment and tool assembly for implanting alongitudinal connecting member in a patient includes at least two spinalimplants, an insertion tool or tools, a bone screw driver and aconnection or reduction tool.

Each spinal implant includes a receiver and a spinal attachment portion,the receiver having a channel for receiving a longitudinal connectingmember. The receiver also has opposed sides with insertion toolattachment structure thereon and an inner surface with a first guide andadvancement structure thereon sized and shaped to receive a closurestructure. The opposed sides of the receiver have a planar surface andthe tool attachment structure includes an undercut running substantiallyparallel to a top surface of the receiver sized and shaped for receivingprojections on the insertion tool. The receiver opposed sides aresubstantially similar, and in some embodiments substantially parallel.In other embodiments, the opposed sides slope toward one another fromnear a bottom to the top of the receiver, forming a trapezoidal profile,the degree of slope corresponding to an actual or desired degree ofsegmental lordosis of a patient's spine. In other embodiments, theopposed sides slope away from one another from near a bottom to the topof the receiver, forming an inverted trapezoidal profile, the degree ofslope corresponding to a degree of actual or desired kyphosis of asegment or segments of a patient's spine. Furthermore, spinal implantsof the invention may be open or closed fixed bone anchors (hooks orscrews), hinged bone screws, or polyaxial bone screws.

As stated above, the tool assembly further includes at least oneinsertion tool, and preferably an insertion tool for each bone anchor orattachment structure. The insertion tool has an elongate body with atop, a bottom, and opposed spinal implant engaging structure near thebottom of the body. The body further has a longitudinal axis, an outersurface and a channel with a lateral opening extending through the outersurface and along the longitudinal axis from a top to a bottom of theinsertion tool. At least a portion of the channel opening is sized andshaped for receiving a longitudinal connecting member, the body furtherhaving an inner surface with a second guide and advancement structuredisposed near the top. The insertion tool implant engaging structure issized and shaped to engage the spinal implant tool attachment structurein only one orientation. A starting location of the second guide andadvancement structure is positioned so as to cooperate with the firstguide and advancement structure of the receiver for precise matingbetween a closure structure and the first guide and advancementstructure and placement of the closure structure at an exact locationwithin the receiver.

Tool assemblies according to the invention also include at least onedriver having a handle, a stem receivable in the insertion tool and adriving end configured for rotatable engagement with the spinal implant.Furthermore, the driver has at least one laterally extending tab sized,shaped and located for engagement with the insertion tool at a surfacedefining the lateral opening of the channel. In the illustratedembodiment, the insertion tool lateral opening includes at least anarrow opening near the top and also a through channel. The driver tabextends through the narrow opening when the driver is received by theinsertion tool with the driving end engaging a spinal implant. Thedriver further includes a second tab extending laterally from thethrough channel when the driver is received by the insertion tool withthe driving end engaging a spinal implant. The driver is sized andshaped to fit snugly within a U-shaped channel formed by opposed arms ofthe spinal implant.

Tool assemblies of the invention further include at least one reductiontool having a handle, a stem receivable in the insertion tool and aretractable driving tip sized and shaped for holding a closure structurethereon in only one orientation. The stem includes a third guide andadvancement structure sized and shaped to mate under rotation with thesecond guide and advancement structure of the insertion tool.

Furthermore, according to the invention closure structures are provided,each having a fourth guide and advancement structure sized and shaped tomate with the first guide and advancement structure of the receiver.Each closure structure has an internal drive for receiving the reductiontool driving tip, the internal drive having a key slot for receiving thereduction tool driving tip in only one location.

A hinged spinal implant according to the invention for fixing alongitudinal connecting member to the spine includes a receiver having apair of opposed arms defining an open channel sized and shaped toreceive a longitudinal connecting member. The receiver further has acentral bore and a lower opening, the bore communicating with both theU-shaped channel and the lower opening. The implant includes a shankhaving an elongate body and an upper end integral with the body. Theupper end has a top surface sized and shaped for frictional engagementwith the longitudinal member. The upper end also has a projectiondisposed substantially perpendicular to the elongate body, theprojection sized and shaped to be received between the arms andslidingly mate with a receiver surface defining a portion of the openchannel, putting the shank in hinged relationship with the receiver,articulating in a plane that includes the pair of opposed arms when theprojection engages the receiver surface with the shank body extendingthrough the lower opening. In the illustrated embodiment, the receiverchannel is U-shaped and the projection is a first projection, with theshank upper end having a second projection extending in a directionopposite the first projection, the first and second projections eachhaving a U-shaped surface. Furthermore, the receiver surface and thefirst and second projections have cooperating teeth for locking theshank into a selected angular position with respect to the receiver. Inone embodiment, the shank is up-loadable into the receiver through thelower opening. In another embodiment, the shank is downloadable into thereceiver through the channel. It is also foreseen that the shank neednot be an integral one piece structure.

A dynamic vertebral support connecting member implantation kit accordingto the invention, adapted for use with a plurality of vertebrae,includes a plurality of hinged, polyaxial or monoaxial bone screws andhooks, each bone anchor being adapted for implantation in or on onevertebra, each of the implants having structure for attachment to aninsertion tool in only one orientation. The kit also includes aplurality of insertion tools, at least one driver, and at least onereduction tool having a retractable tip for holding a closure structure.Other tools may be included in the kit such as, but not limited to aclosure starter. Also provided in the kit are a plurality of closurestructures having a key slot or other structure such that the closurestructures may be held by the reduction tool in only one orientation.

A method according to the invention includes the steps of providing atleast first and second insertion tools, each tool releasably attachableto a bone screw or hook, each end guide tool having an elongate channelwith a lateral opening extending the length, at least a portion of theopening for receiving a longitudinal connecting member, an inner surfaceof the tool having a guide and advancement structure thereon with astarting location placed for exact mating and placement of a closurestructure within a bone screw or hook.

The method further includes attaching each insertion tool to a bonescrew, for example, and inserting a driving tool into the insertion toolchannel with or without a tab of the driving tool extending through theinsertion tool lateral opening, followed by driving the bone screw intoa vertebra by rotating the driving tool, insertion tool and bone screwassembly. Then, a longitudinal connecting member is inserted into thelateral openings of each insertion tool.

The method also includes providing a closure structure for each bonescrew, each closure structure having a drive structure sized and shapedfor releaseable attachment to a reduction tool. Also, the methodincludes providing a reduction tool having a retractable driving tipsized and shaped to hold a closure structure in only one orientation,the reduction tool also having a guide and advancement structure thereonsized and shaped to mate with the guide and advancement structure on theinsertion tool. The reduction tool with attached closure structure isinserted into the channel of the insertion tool and rotated, driving thelongitudinal connecting member downward into the bone screw and rotatingthe closure structure into precise mating engagement with the bonescrew.

Objects and Advantages of the Invention

Therefore, the objects of the present invention are: to provide acompact tool assembly for supporting and installing bone attachmentstructures, such as bone screws, hooks and dynamic stabilizationconnecting members and other spinal implants with minimal or lesssurgical invasion to the patient; to provide both hinged and fixed openbone screws and hooks for cooperation with dynamic stabilizationconnecting members; to provide open and closed lordosing and kyphosingimplants (screws and hooks) for use in such an assembly; to provide aset of tools for implanting a dynamic spinal fixation connecting memberfor support or alignment along a human spine with minimal or lesssurgical invasion of the patient; to provide such a set of toolsincluding an insertion tool, driving, reduction and manipulation toolsfor use in implanting a bone attachment implant, directing alongitudinal connecting member downwardly into such an implant andcapturing the longitudinal connecting member within a receiver of thebone attachment implant; to provide such a set of tools including aclosure reduction and installation tool for securing the dynamicfixation connecting member to the bone attachment implant; to providesuch a set of tools wherein the insertion, driving and manipulationtools are easily attached to and disengaged from the bone attachmentimplants; to provide such a set of tools wherein the insertion tools,supports or stabilizers, deployment tools, reduction tools, bone implantinstallation tools and closure installation tools are all easilyaligned, positioned, and engaged, if necessary, with respect to the boneimplants and are disengaged from the bone implants and other tools inthe installation assembly by manual manipulation of the surgeon; toprovide a method of implanting a dynamic stabilization connecting memberinto bone implants within a patient with minimal or less surgicalinvasion of the patient; to provide such a method utilizing thepreviously described tools for implantation of such a connecting member;and to provide such a set of tools and methods that are easy to use andespecially adapted for the intended use thereof and wherein the toolsare comparatively inexpensive to produce.

Other objects and advantages of this invention will become apparent fromthe following description taken in conjunction with the accompanyingdrawings wherein are set forth, by way of illustration and example,certain embodiments of this invention.

The drawings constitute a part of this specification and includeexemplary embodiments of the present invention and illustrate variousobjects and features thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a hinged bone screw assemblyaccording to the present invention having a shank, a receiver and shownwith a closure structure.

FIG. 2 is an enlarged cross-sectional view of the shank taken along theline 2-2 of FIG. 1.

FIG. 3 is an enlarged top plan view of the receiver of FIG. 1.

FIG. 4 is an enlarged side elevational view of the receiver of FIGS. 1and 3.

FIG. 5 is an enlarged top plan view of the closure structure of FIG. 1.

FIG. 6 is an enlarged cross-sectional view of the receiver taken alongthe line 6-6 of FIG. 1 and the shank of FIG. 1 in partial frontelevation, showing an initial stage of attachment of the shank to thereceiver.

FIG. 7 is an enlarged cross-sectional view of the receiver taken alongthe line 6-6 of FIG. 1 and the shank of FIG. 1 in partial sideelevation, rotated ninety degrees and lowered into a seated positionwithin the receiver.

FIG. 8A is an enlarged cross-sectional view, similar to FIG. 7, furthershowing the shank in cross-section along the line 8-8 of FIG. 1, withthe shank disposed at an angle with respect to the receiver and furthershowing an extent of articulation in phantom. FIG. 8B is an enlargedfront elevational view of the shank implanted in a vertebra, shown withthe first receiver and the longitudinal connecting member and also shownwith a replacement receiver and a second, larger cooperatinglongitudinal connecting member.

FIG. 9 is an enlarged perspective view of first and second hinged bonescrews according to FIG. 1 shown with a longitudinal connecting memberin the form of a cord and cord receiving spacer.

FIG. 10 is an exploded and partial front elevational view of a toolassembly according to the present invention showing a lock pin, aninsertion tool and the bone screw of FIG. 1.

FIG. 11 is a top plan view of the insertion tool of FIG. 10.

FIG. 12 is a cross-sectional view taken along the line 12-12 of FIG. 10.

FIG. 13 is a bottom plan view of the insertion tool of FIG. 10.

FIG. 14 is a side elevational view of the insertion tool of FIG. 10.

FIG. 15 is a cross-sectional view taken along the line 15-15 of FIG. 14.

FIG. 16 is a partial cross-sectional view taken along the line 16-16 ofFIG. 15.

FIG. 17 is a partial cross-sectional view taken along the line 17-17 ofFIG. 15.

FIG. 18 is an enlarged and partial view of the insertion tool of FIG. 10with portions broken away to show the detail thereof.

FIG. 19 is an enlarged front elevational view of a lock pin driveraccording to the invention shown mounted on a lock pin installed to theinsertion tool of FIG. 10, shown in partial front elevation.

FIG. 20 is an enlarged top plan view of the lock pin driver of FIG. 19.

FIG. 21 is an enlarged bottom plan view of the lock pin driver of FIG.19.

FIG. 22 is a cross-sectional view taken along the line 22-22 of FIG. 20.

FIG. 23 is an enlarged and partial front elevational view of theinsertion tool and bone screw of FIG. 10, showing the bone screwattached to the insertion tool and with two lock pins.

FIG. 24 is an enlarged and exploded front elevational view of a bonescrew driver according to the invention and the insertion tool andattached bone screw of FIG. 23.

FIG. 25 is an enlarged bottom plan view of the driver of FIG. 24.

FIG. 26 is an enlarged and partial side elevational view of the driverof FIG. 24.

FIG. 27 is an enlarged and exploded front elevational view of areduction tool according to the invention and the insertion tool andattached bone screw of FIG. 24, also shown with the closure structure ofFIG. 1 and a longitudinal connecting member.

FIG. 28 is an enlarged and partial bottom plan view of the reductiontool of FIG. 27.

FIG. 29 is an enlarged and partial front elevational view similar toFIG. 27, showing the reduction tool received in the insertion tool andengaged with the closure structure.

FIG. 30 is an enlarged and partial front elevational view of an upperportion of the reduction tool of FIG. 28 with portions broken away toshow the detail thereof, a driving shaft being shown in an extendedposition.

FIG. 31 is an enlarged and partial front elevational view of the upperportion of the reduction tool of FIG. 27 with portions broken away toshow the detail thereof, the driving shaft being shown in a retractedposition.

FIG. 32 is an enlarged cross-sectional view taken along the line 32-32of FIG. 30.

FIG. 33 is an enlarged and partial front elevational view of a lowerportion of the reduction tool of FIGS. 27 and 30, shown engaged with theclosure structure and reducing a longitudinal connecting member alongthe insertion tool of FIG. 27 and toward the attached bone screw.

FIG. 34 is an enlarged and partial front elevational view similar toFIG. 33 with portions broken away to show the detail thereof and furthershowing the closure structure fully seated in the bone screw.

FIG. 35 is an enlarged and partial front elevational view similar toFIGS. 33 and 34, further showing the reduction tool in the retractedposition of FIG. 31 and being moved away from a fully seated bone screw.

FIG. 36 is a partial and exploded front elevational view of a closurestructure starter for use in accordance with the invention, furthershown with a closure structure, a cord, and an insertion tool andattached bone screw.

FIG. 37 is a partial and generally schematic view of a patient's spineshowing a bone screw driver received within an insertion tool with anattached bone screw being guided toward a threaded bore in a vertebra inan early stage of a method according to the invention.

FIG. 38 is a partial and generally schematic view of a patient's spine,showing an implanted bone screw with attached insertion tool receiving areduction tool engaged with a closure structure.

FIG. 39 is a partial and generally schematic view of a patient's spine,showing three insertion tools, each attached to an implanted bone screwand further showing a stage of implantation of a cord and threadedspacers.

FIG. 40 is a front elevational view of a first alternative monoaxialbone screw according to the invention having an open receiver.

FIG. 41 is a side elevational view of the bone screw of FIG. 40.

FIG. 42 is a top plan view of the bone screw of FIG. 40.

FIG. 43 is a side elevational view of a second alternative monoaxialbone screw according to the invention having an open receiver andtrapezoidal profile.

FIG. 44 is a partial side elevational view of a third alternativemonoaxial bone screw according to the invention having an open receiverand trapezoidal profile.

FIG. 45 is a partial side elevational view of a fourth alternativemonoaxial bone screw according to the invention having an open receiverand reverse trapezoidal profile.

FIG. 46 is a partial side elevational view of a fifth alternativemonoaxial bone screw according to the invention having an open receiverand reverse trapezoidal profile.

FIG. 47 is a side elevational view of a sixth alternative monoaxial bonescrew according to the invention having a closed receiver and reversetrapezoidal profile.

FIG. 48 is a partial side elevational view of a seventh alternativemonoaxial bone screw according to the invention having a closed receiverand trapezoidal profile.

FIG. 49 is a partial side elevational view of an eighth alternativemonoaxial bone screw according to the invention having a closed receiverand trapezoidal profile.

FIG. 50 is a partial and generally schematic view of a patient's spine,showing two implanted monoaxial bone screws according to FIGS. 40-42with a connecting cord and spacer having non-parallel end surfaces.

FIG. 51 is a partial and generally schematic view of a patient's spine,showing two implanted bone screws according to FIG. 43 with a connectingcord and spacer.

FIG. 52 is a perspective and partially exploded view of an alternativehinged screw according to the invention including a shank, a receiverand an attachment clip.

FIG. 53 is an enlarged and partial front elevational view of the hingedscrew of FIG. 52 and shown in a second position in phantom.

FIG. 54 is an enlarged top plan view of the attachment clip of FIG. 51.

FIG. 55 is an enlarged and exploded perspective view of a polyaxial bonescrew assembly according to the invention shown with a dynamiclongitudinal connecting member for use according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodimentsare merely exemplary of the invention, which may be embodied in variousforms. Therefore, specific structural and functional details disclosedherein are not to be interpreted as limiting, but merely as a basis forthe claims and as a representative basis for teaching one skilled in theart to variously employ the present invention in virtually anyappropriately detailed structure.

With reference to FIGS. 1-38, the reference numeral 1 generallydesignates a hinged bone screw for cooperation with a dynamicstabilization connecting member, generally 3, such as the illustratedcord 6 with cannulated spacers 8. The spacers 8 are substantiallycylindrical with opposed planar sides 9. Tools for implanting a bonescrew 1 on a vertebra 10 of a human spine 12 and manipulatingcooperating bone screws 1 and longitudinal connecting members 3 mayinclude one or more insertion tools, generally 14, a bone screw driver16, a reduction tool 18, and a closure starter 20.

The hinged bone screw assembly 1 includes a shank 24 and a receiver 26.A closure structure 28 is further included for engagement with thereceiver to capture and fix the cord 6 of the longitudinal connectingmember 3 within the receiver. The shank 24 further includes a body 36integral with an upwardly extending end portion 38. The shank 24 and thereceiver 26 are assembled prior to implantation of the shank body 36into the vertebra 10. It is noted that any reference to the words top,bottom, up and down, and the like, in this application refers to thealignment shown in the various drawings, as well as the normalconnotations applied to such devices, and is not intended to restrictpositioning of the bone screw assembly 1 and tools 14, 16, 18 and 20 inactual use.

The shank 24 of the bone screw assembly 1, best illustrated in FIGS. 1,2 and 6-9, is elongate, having an axis of rotation A. The shank body 36has a helically wound, radially outwardly extending bone implantablethread 40 axially extending from near a lower end or tip 44 of the body36 to near a slanted or sloped surface 46 that is adjacent to a smoothsubstantially cylindrical surface 48 located adjacent to the end portion38. During use, the body 36 utilizing the thread 40 for gripping andadvancement is implanted into the vertebra 10 leading with the tip 44and driven down into the vertebra 10 with the driving tool 16 so as tobe implanted in the vertebra 10 to near the sloped surface 46.

To provide a biologically active interface with the bone, an outersurface 50 of the shank body 36 that includes the thread 40 and extendsbetween the surface 46 and the tip 44 is coated, perforated, made porousor otherwise treated 52. The treatment 52 may include, but is notlimited to a plasma spray coating or other type of coating of a metalor, for example, a calcium phosphate; or a roughening, perforation orindentation in the surface 50, such as by sputtering, sand blasting oracid etching, that allows for bony ingrowth or ongrowth. Certain metalcoatings act as a scaffold for bone ingrowth. Bio-ceramic calciumphosphate coatings include, but are not limited to: alpha-tri-calciumphosphate and beta-tri-calcium phosphate (Ca₃(PO₄)₂, tetra-calciumphosphate (Ca₄P₂O₉), amorphous calcium phosphate and hydroxyapatite(Ca₁₀(PO₄)₆(OH)₂). Coating with hydroxyapatite, for example, isdesirable as hydroxyapatite is chemically similar to bone with respectto mineral content and has been identified as being bioactive and thusnot only supportive of bone ingrowth, but actively taking part in bonebonding.

The sloped surface 46 extends radially inward and axially upward fromthe shank body 36 to the cylindrical portion 48. Further extendinglaterally outwardly from the cylindrical portion 48 is the upper endportion 38 that provides a connective or capture apparatus disposed at adistance from the threaded shank body 36 and thus at a distance from thevertebra 10 when the body 36 is implanted in the vertebra 10. The upperend portion 38 is configured for connecting the shank 24 to the receiver26 and capturing the shank 24 in the receiver 26. For instance, withreference to FIG. 8B, receiver 26 may include a change out feature,allowing for removal of receiver 26 from shank 24 without removing theshank 24 from the vertebra 10. The receiver 26 may then be replaced witha second receiver 26A for accommodating, e.g., a more rigid longitudinalconnecting member of a different size 6A. The upper end portion 38 has apair of projections or wings 56 that extend laterally oppositelyoutwardly from the cylindrical surface 48. Each projection 56 has alower curved, convex surface 57 with ridges or locking teeth 58 sizedand shaped to engage a concave toothed surface of the receiver 26, to bedescribed more fully below. The locking teeth 58 are sized and shaped toprovide locking positions at about every ten degrees for a total rangeof hinged motion of about sixty degrees, about thirty degrees on eitherside of a central axis B of the receiver 26 as illustrated in FIG. 8.The upper or end portion 38 further includes a top surface 60 thatincludes a concave portion sized and shaped for receiving and engagingthe driver 16 as will be described more fully below and also the cord 6.A side surface 62 extends between the top surface 60 and each curvedlower surface 57.

In the illustrated embodiment, the shank 24 is cannulated with a smallcentral bore 66 extending an entire length of the shank along the axisA. The bore 66 is coaxial with the threaded body 36 and opens at the tip44 and the top surface 60, providing a passage through the shankinterior for a length of wire or pin inserted into the vertebra 10 priorto the insertion of the shank body 36, the wire or pin providing a guidefor insertion of the shank body 36 into the vertebra 10.

With reference to FIGS. 1, 3, 4 and 6-8, the receiver 26 includes a base70 integral with a pair of opposed upstanding arms 72 and 73 that extendfrom the base 70 to respective top surfaces 74 and 75. The arms 72 and73 form a U-shaped cradle and define a U-shaped channel 76 between thearms 72 and 73 and include an upper opening 77 and a lower seat 78. Thelower seat 78 includes locking teeth 80 sized and shaped to engage thelocking teeth 58 of the shank upper end portion 38. Each of the arms 72and 73 has an interior surface that defines an inner cylindrical profileand includes a discontinuous helically wound guide and advancementstructure 82. In the illustrated embodiment, the guide and advancementstructure 82 is a partial or discontinuous helically wound flangeformconfigured to mate under rotation with a similar structure on thesubstantially cylindrical closure structure 28, as described more fullybelow. However, it is foreseen that the guide and advancement structure82 could alternatively be a buttress thread, a square thread, a reverseangle thread or other thread like or non-thread like helically woundadvancement structures for operably guiding under rotation and advancingthe closure structure 28 downward between the arms 72 and 73 and havingsuch a structural nature as to resist splaying of the arms 72 and 73when the closure 28 is advanced into the U-shaped channel 76 andtightened.

Each of the arms 72 and 73 has a substantially planar outer surface 84and 85, respectively, that includes a substantially linear undercut toolengagement groove 86 and 87, respectively, V-shaped in cross-section andformed in the receiver 26 near the respective top surfaces 74 and 75.Sloping surfaces 88 and 89 run inwardly and upwardly from the respectiveouter surfaces 84 and 85 to the respective grooves 86 and 87. TheV-shaped grooves 86 and 87 secure the insertion tool 14 to the bonescrew receiver 26 during implantation of the screw into bone andmanipulation of the longitudinal connecting member 3 and closurestructure 28, and in cooperation with the sloping surfaces 88 and 89,allows for easy, sliding release of the tool 14 from the bone screwduring removal of the tool at the end of the procedure. The grooves 86and 87 cooperate with projections of the insertion tool 14, which willbe described in greater detail below, the insertion tool projectionsbeing received in the grooves 86 and 87 during implantation of the shankbody 36 into the vertebra 10 and subsequent installation of theconnecting member 3 and closure structure 28. Upper ledges 90 and 91adjacent to top surfaces 74 and 75, respectively, extend laterally fromthe respective receiver surfaces 84 and 85 and from a substantiallyplanar side 92 to an opposite planar side 93, partly defining therespective undercut grooves 86 and 87. Each ledge 90 and 91 includes anarrow opening or slit 94 and 95, respectively, formed therein andrunning from the top surface 74 and 75 to respective side surfaces 84and 85. The slits 94 and 95 run parallel with the axis B of thereceiver. The ledges 90 and 91 are substantially similar in size andshape with the exception of the position and size of the slits 94 and95. The slit 94 is located substantially centrally in the ledge 90 whilethe slit 95 is substantially off-center and also wider than the slit 94,such width measured in a direction perpendicular to the axis B. As willbe described more fully below, the slits 94 and 95 cooperate withprojections on the insertion tool 14 and cooperate and attach to thetool 14 in only one location and thus there is only one way in which toorient and attach the tool 14 to the receiver 26. It is foreseen thatthe slits 94 and 95 may be of a variety of sizes and shapes withcooperating structure on the insertion tool 14 such that the tool 14will only attach to the receiver 26 in a single position or orientation,resulting in a desired precise alignment between the bone screw 1, theinsertion tool 14 and thereafter, the reduction tool 18. The receiverarm outer side surface 72 further includes a laser or otherwise etchedalignment stripe 98 running parallel to the axis B. The stripe 98corresponds to a similar stripe 100 on the insertion tool 14(illustrated in FIGS. 38 and 39), providing a visual aid and ease in thealignment and proper attachment of the insertion tool 14 with thereceiver 26 by aligning the stripe 98 with the stripe 100.

Communicating with the U-shaped channel 76 and located within the base70 of the receiver 26 is a chamber or cavity 102 that opens upwardlyinto the U-shaped channel 76 and communicates and opens downwardly to anoblong lower opening or neck 104 in the base 70. The lower opening 104communicates with an outer lower exterior or bottom 105 of the base 70.The base lower opening 104 and the cavity 102 are sized and shaped toreceive the upper end portion 38 of the shank 24 as illustrated in FIG.6. The cavity 102 is defined in part by upper ceiling or stop surfaces106 disposed on either side of the channel 76, the surfaces 106 prohibitthe end portion 38 from being advanced through the channel 76 to thereceiver upper opening 77 when the upper portion 38 is in a loadingorientation, receivable in the oblong lower opening 104. Stateddifferently, the shank 24 is bottom loaded into the receiver 26, withthe upper portion 38 being disposed at an upper portion of the cavity102 when the upper portion 38 is in the loading orientation, as shown inFIG. 6. The cavity 102 is also partially defined by opposed innersurfaces 107 that extend from the opening 104 to the upper surfaces 106.As will be described in further detail below, to seat the upper portion38 in the receiver 26, the upper portion 38 is slid upwardly along thesurfaces 107, then rotated ninety degrees about the receiver axis Bwithin the cavity 102 and thereafter lowered toward the opening 104 asillustrated in FIG. 7 to seat the upper end portion 38 curved surface 57on the receiver lower seat 78, with the teeth 58 engaging the teeth 80.The cavity 102 is sized and shaped to accommodate the rotation of thewing projections 56 of the upper end portion 38 about the axis B. Oncerotated, the neck 104 is sized and shaped to have a width that issmaller than the shank upper portion 38 measured along the wingprojections 56 so as to form a restriction at the location of the neck104 relative to the winged upper portion 38, to prevent the upperportion 38 from passing from the cavity 102 and out into the lowerexterior 105 of the receiver 26 when the upper portion 38 is seated onthe lower seating surface 78. Communication between the curved surface57 and the lower seat 78 allow for articulated or hinged motion of theshank 24 with respect to the receiver 26 in a single plane asillustrated in FIG. 8, with the teeth 58 and 80 providing for fixedengagement between the shank 24 and the receiver 26 when a force isplaced on the shank end portion 38 by rotating and torquing the closurestructure 28 against the cord 6 of the longitudinal connecting member 3.The hinged motion of the shank 24 is limited by the cylindrical surface48 of the shank 24 abutting the oblong neck 104 near either outer side84 and 85 of the receiver 26.

With particular reference to FIG. 9, the illustrated longitudinalconnecting member 3 includes from one up to a plurality of cannulatedspacers 8 sized and shaped to receive the cord 6 therethrough. Thespacers 8 are also sized and shaped to fit between pairs of bone screws1, cooperating with the cord 6 to support adjacent vertebrae whenimplanted between bone screws 1. The spacers 8 may be made of a varietyof materials including metals, plastics and composites. The illustratedspacer is made from a plastic, such as polycarbonate-urethane. Theillustrated cord is also made from plastic, such aspolyethylene-terephthalate. The spacer/cord combination provides for aflexible anatomical holding and control of the spinal motion segment orsegments to be treated. It is also foreseen that other longitudinalconnecting members may be utilized with the bone screws or otherimplants according to the invention, including solid rods and dynamicstabilization connecting members and member assemblies including, butnot limited to coils, springs, and coil or spring and rod combinationsincluding coils having rod-like inserts. Such connecting members canprovide for protected motion, including torsional elasticity and elasticaxial compression and distraction in addition to flexibility.

The closure structure 28 closes between the spaced bone screw arms 72and 73 to secure the connecting member 3 in the channel 76. The closurestructure 28 can be any of many different plug type closures. Withparticular reference to FIGS. 1 and 5, the illustrated closure structure28 has a cylindrical body 108 that has a helically wound mating guideand advancement structure 110. The illustrated guide and advancementstructure 110 is a helically wound flangeform that interlocks with areciprocal flangeform of the guide and advancement structure 82 of thereceiver 26. However, it is foreseen that as with the guide andadvancement structure 82, the structure 110 can be of any type,including V-type threads, buttress threads, reverse angle threads, orsquare threads, that cooperate with the guide and advancement structure82 on the bone screw arms 72 and 73. A suitable flangeform locking guideand advancement structure is disclosed in U.S. Pat. No. 6,726,689, whichis incorporated herein by reference.

The closure structure 28 further includes a top surface 112 and asubstantially planar bottom surface 113, the bottom surface 113providing a smooth contact surface for engagement with a cord 6 of thelongitudinal connecting member 3. Formed in the top surface 112 is asubstantially hex-shaped internal drive socket or aperture 115, furtherincluding a key slot 116 for precise and particular engagement with thereduction tool 18 as will be described in further detail below. Althougha hex-shaped drive 115 is illustrated herein, it is foreseen that theclosure structure internal drive may be of other shapes or sizes.Alternatively, the closure structure 28 may include an external drivinghead that breaks away from the cylindrical body 102 upon the applicationof a preselected torque.

The insertion tool 14 is best illustrated in FIGS. 10-18. In particular,the tool 14 has an elongate body 118 and two cooperating lock pins 120.The elongate body 118 has an axis of rotation C and is sized and shapedto be sufficiently long to extend from an implanted bone screw 1 throughan exterior of a patient's skin so as to provide an outwardly extendingand upper handle portion 122 that allows and provides for gripping by asurgeon during procedures utilizing the insertion tool 14, with orwithout a driver 16, a reduction tool 18 or a closure starter 20. Theinsertion tool 14 further includes an intermediate portion 124 and alower implant engaging portion 126 which includes opposed implantengaging members or tangs 128 and 129 for securing a bone screw 1 orother implant there between.

With reference to FIGS. 11-13, the insertion tool 14 has a generallyrectangular shape when viewed on end or in a cross section takenperpendicular to the axis of rotation C. The tool 14 further forms anopen channel 132 running along the axis C from a top surface 134 tobottom surfaces 136 thereof. The channel 132 is substantially defined byan inner discontinuous cylindrical wall 138. The wall 138 is sized andshaped to receive the driving and manipulating tools 16, 18 and 20 aswill be described in greater detail below. The tool 14 further includesa front 140 and opposed back 142, and opposed sides 144 and 146 thatattach the front 140 to the back 142. The back 142 includes an uppersubstantially solid wall portion 147. With reference to FIGS. 38 and 39,the side 144 includes the laser etched alignment stripe 100 that aids asurgeon in properly aligning and mating the tool 14 with the receiver 26by simply aligning the stripe 100 with the stripe 98 that is located ononly one side 84 of the receive 26. As illustrated in FIG. 14, the side146 is substantially planar and solid and is integrally joined to thefront 140 and the back 142 substantially along a length thereof parallelto the axis C. The opposite side 144 is integral to the back 142substantially along an entire length thereof parallel to the axis C. Theside 144 is also integral with the front 140 along the intermediate 124and lower 126 portions of the tool 14. It is foreseen that thecross-sectional shape of the tool 14 could be rounded or some othershape.

A through channel 148 is formed in both the front 140 and the back 142portions of the tool 14 and communicates with the longitudinal channel132. The openings and channels described herein with respect to the tool14 are sized and shaped to receive and allow passage of both tools andimplants as will be described more fully below. The through channel 148begins near the upper handle portion 122 and extends through the bottomsurfaces 136 of the tangs 128 and 129 that define a lower portion of thechannel 148 and the lower, implant engaging portion 126 of the tool 14.

With respect to the axis C, the beginning of the through channel 148near the upper portion 122 is of a staggered arrangement. A squared off,discontinuous and off-center opening 149 is formed in the front 140opposite the solid portion 147 of the back 142, the opening 149partially defined by a first corner 150 formed in the front 140 and asecond corner 151 formed in the side 144, the opening 149 communicatingwith an upper more narrow channel 152 that extends from the opening 149through the top surface 134. The opening 149 then extends along thefront 140 all the way through the bottom surfaces 136 of the tool 14,communicating with the open longitudinal channel 132. As will bediscussed more fully below, the opening 149 is sized and shaped toreadily receive a driving end of the bone screw driver 16, the lowerhousing and retractable driving tip of the reduction tool 18 and the tipof the closure starter 20, as well as the entire closure structure 28.The lateral opening of the narrow channel 152 is sized and shaped toreceive slender shafts of the driver 16, reduction tool 18 and closurestarter 20. Thus, the opening 149 communicating with both the narrowchannel 152 and the through channel 148 provides for a continuouslateral or side opening along an entire length of the tool 14 along theaxis C that is sized and shaped to receive longitudinal connectingmembers including, but not limited to cords 6, coils and rods, as wellas closure implants and various manipulating tools. Near the corner 150,the opening 149 also is partially defined by a cut-out portion of thefront 140 that exposes the side 144 of the tool 14. The opening 149includes an elongate wall 154 in the side 144 that faces toward thefront 140 and a lower or base surface 155 that runs perpendicular to theaxis C. Above the corner 150, the wall 154 widens to form an upperportion 156 that extends to the top 134 of the tool 14, the upperportion 156 partially defining the upper narrow channel 152.

At the back 142 of the tool 14, a U-shaped opening 157 formed in theupper back portion 147 marks the beginning of the through channel 148that extends through the back 142 and downwardly through the bottomsurfaces 136. Thus, the through channel 148 that extends through thefront opening 149 and the back opening 157, begins at the U-shapedopening 157 and is substantially uniform in width measured perpendicularto the axis C over the intermediate 124 and lower 126 portions of thetool 14, being substantially defined by the sides 144 and 146 that endin the tangs 128 and 129. The through channel 148 thus provides for someflexibility to allow for outward splaying of the tangs 128 and 129 nearthe bottom surfaces 136 and about the receiver 26 of the bone screwshank 1 as will be described in greater detail below.

With particular reference to FIGS. 11-13 and 18, near the intersectionof the front 140 and the side 146, a narrow cylindrical side channel 158is formed in the tool 14, running parallel to the axis C and partiallydefined by a threaded inner wall 160, the channel 158 and threaded wall160 sized and shaped to rotatingly receive a first lock pin 120. At anopposite corner of the tool 14 at the intersection of the back 142 andthe side 144, a second narrow cylindrical side channel 162 is formed inthe tool 14, parallel to the axis C and having a threaded inner wall164, the channel 162 and threaded wall 164 also sized and shaped forrotatingly receiving a lock pin 120. The channels 158 and 162 are openat both ends 134 and 136, with the threaded portions 160 and 164 beinglocated near the top 134 in the upper portion 122 of the tool 14.

Also near the top 134 and within the upper portion 122 of the tool 14 isa discontinuous guide and advancement structure 168 disposed on theinner cylindrical wall 138 defining the central channel 132. The guideand advancement structure 168 is a substantially square thread sized andshaped to receive a cooperating guide and advancement structure of thereduction tool 18 to be described more fully below. A starting location170 of the guide and advancement structure 168 on the insertion tool 14is coordinated with a starting position of the guide and advancementstructure on the reduction tool 18 and a starting location of the guideand advancement structure 82 of the bone screw receiver 26 when attachedto the insertion tool 14, so as to provide for exact closure structurealignment and engagement within the receiver 26 to a specific, fullyseated position, as also will be described more fully below.

The front 140 of the tool 14 includes two outer front faces 172 and 173that are substantially similar in size and are spaced from one another,with the through channel 148 extending therebetween. The face 172 beginsadjacent to the bottom 155 of the cut-out portion of the opening 149 andextends to the bottom surface 136. The face 173 extends an entire lengthof the tool along the axis C. The face 173 widens at an upper or topportion 175 of the front 140. The portion 175 partly defines the narrowchannel 152 and supports the guide and advancement structure 168.

Near the bottom surfaces 136, both the faces 172 and 173 include acut-out or recess 178 that extends into the sides 144 and 146,respectively, and is defined in part by the tangs 128 and 129,respectively. With particular reference to FIG. 23, the cut-outs 178 areeach defined by an upper surface 180 disposed perpendicular to the axisC, an inner planar surface 182 disposed parallel to the axis C and asubstantially planar lip surface 184 disposed at an acute angle withrespect to the surface 182. The lip surface 184 is on each of a pair ofopposed projections or implant engaging members 186 and 187, disposed onrespective tangs 128 and 129, each projecting toward the axis C andsized and shaped to engage and slidingly fit within the grooves 86 and87 respectively, of the receiver 26.

With particular reference to FIGS. 16 and 17, the inner surface 182disposed above the projection 186 further includes a raised strip orprojection 194 that runs parallel to the axis C and is sized, shaped andpositioned to slidingly engage with the slit 94 in the ledge 90 of thearm 72 of the receiver 26. The inner surface 182 disposed above theprojection 187 further includes a raised strip or projection 195 thatalso runs parallel to the axis C and is sized, shaped and positioned toslidingly engage with the slit 95 in the ledge 91 of the arm 73 of thereceiver 26. As will be described in greater detail below and withreference to FIG. 23, the cooperation between the strip 194 and the slit94 and the strip 195 and the slit 95 ensures proper alignment and matingof the insertion tool 14 and the receiver 26 and further prohibits frontto back movement of the receiver 26 with respect to the insertion tool14 when the tool 14 is mounted on the receiver 26 and the lock pins 120contact respective top surfaces 74 and 75 of the receiver 26.

Each lock pin 120 is elongate, having a top surface 200 a curved bottomsurface 202, a hex-shaped upper driving portion 204 disposed near thetop surface 200 and a threaded portion 206 disposed near the drivingportion 204 and on a smooth cylindrical body portion 207 of the lock pin120. The smooth body portion 207 extends from the driving portion 204 tothe bottom surface 202. As illustrated in FIG. 10, near the bottomsurface 202, the body portion 207 may be of slightly reduced diameter asshown by the portion 208 to result in the bottom surface 202 being of asize and shape to fully contact the receiver 26 without overhang. Thelock pin 120 is sized and shaped to be received in either of thecylindrical channels 158 and 162 in the insertion tool 14, with thethreaded portion 206 rotatably receivable in either of the threadedinner walls 160 and 164. The lock pin 120 is sized and shaped to extendalong and completely through either of the channels 158 and 162 untilthe curved bottom 202 abuts the top surface 74 or 75 of the receiver 26with the upper driving portion 204 extending above the top 134 of theinsertion tool 14 as illustrated, for example, in FIGS. 19 and 24.

The lock pins 120 are rotated and driven downwardly into the insertiontool 14 by a lock pin driver 210 illustrated in FIGS. 19-22. The lockpin driver 210 includes a substantially cylindrical elongate body 212having an axis of rotation D and shown with outer grooves 214 to aid asurgeon in handling and rotating the driver 210. The driver furtherincludes an upper projection or extension 216 that may be used to spreadthe tangs 128 and 129 of the insertion tool 14 when attaching theinsertion tool 14 to a receiver 26 as will be described in greaterdetail below. The extension 216 has a substantially rectangularcross-section viewed in a plane perpendicular to the axis D. Inparticular, the extension includes a pair of substantially planaropposed sides 217, a pair of substantially curved opposed sides 218 anda curved top surface 219. The body 212 further includes an inner, curvedentry aperture or easement 220 located opposite the extension 216 and anelongate hex-shaped aperture or driving socket 222 running along theaxis D and communicating with the easement 220. The driving socket 222is sized and shaped to receive and mate with the hex-shaped upperdriving portion 204 of each of the lock pins 120. The socket 222includes a stop or abutment surface 224, sized and shaped for frictionalcontact with the top surface 200 of the lock pin 120. Above the abutmentsurface 224 and extending through the upper extension 216, theillustrated lock pin driver 210 is substantially solid.

With reference to FIGS. 24-26, the bone screw driver 16 includes anupper elongate handle 230, an elongate shaft 232 and a driving endportion 234 integral with or fixedly attached to the shaft 232. Thehandle 230 is somewhat triangular when viewed on end as shown in FIG.25. With reference to FIG. 24, the handle 230 includes shallow apertures236 to aid a surgeon in gripping and rotating the handle 230. The handle230 is fixed to and coaxial with the shaft 232 that has an axis ofrotation E. Protruding laterally from the shaft 232 are an alignment tab238 and a centering tab 240, the centering tab 240 being disposedbetween the alignment tab 238 and the driving end 234. With reference tothe axis E, both of the tabs 238 and 240 extend radially outwardly fromthe shaft 232 as illustrated in FIGS. 24, 25 and 37. However, the tabs238 and 240 are not substantially co-linear or co-planar. The two tabs238 and 240 are sized, shaped and positioned to align with non-linearopenings and/or surfaces in the insertion tool 14 to ensure properengagement of the driver 16 driving end 234 within the U-shaped channel76 of the bone screw receiver 26. Specifically, such proper engagementoccurs when the alignment tab 238 is disposed in and extending throughthe channel 152 and the centering tab 240 is disposed in the throughchannel 148 below the surface 155 and abutting against the front face172 as illustrated in FIG. 37 and will be described in greater detailbelow.

Near the driving end 234, the shaft 232 includes a lower portion 242 ofreduced diameter. The driving end 234 further includes a curved lowersurface 244 that smoothly transitions to opposed planar surfaces 245,the surfaces 244 and 245 being sized and shaped to be snugly receivedwithin the receiver U-shaped channel 76 and to fully engage innersurfaces of the arms 72 and 73 as well as the top curved surface 60 ofthe shank end portion 38. Opposed front and rear surfaces 246 of thedriving end 234 are substantially planar and sized and shaped to besubstantially flush with the receiver 26 along the sides 92 and 93, andextending from near the top surfaces 74 and 75 to the seating surface78.

The driving tool 16 includes a longitudinal through bore 248 formedalong an entire length thereof along the axis E. The through bore 248cooperates with cannulated bone screws, allowing for insertion of thedriver 16 and attached bone screw 1 over guide wires or pins.

With reference to FIGS. 27-29, the reduction tool 18 is elongate, havingan axis of rotation F and including a handle 260 that houses a drivingtip extension and retraction mechanism, generally, 262, an upper shafthousing 264, a mid-shaft housing 266 having a threaded portion 268 and alower shaft housing 270 attached to a driving tip housing 272 for anextendible driving tip 273. The handle, shaft housings and driving tipare all aligned along the axis of rotation F. The handle 260 furtherincludes an upper end portion or palm handle 276 a lower grip portion278 and a rotatable member or retraction lever 280 disposed between theupper 276 and lower 278 portions, the rotatable member or lever 280being part of the extension and retraction mechanism 262.

With further reference to FIGS. 30-35, the lever 280 has a coarse innerthread 282 providing for a vertical travel distance to fully andaccurately extend and retract the driving tip 273 in and out of thedriving tip housing (in the illustrated embodiment, a vertical traveldistance of about 3.5 mm) for a ¼ rotation of the lever 280. Themechanism 262 further includes an elongate shaft 285 attached to thedriving tip 273 and extending along the axis F from the driving tip 273to an upper screw 288 disposed substantially within the rotatable lever280 when the driving tip 273 is in an extended, closure member engagingposition as shown in FIGS. 27, 29, 30, 33 and 34. The screw 288 is fixedto the shaft 284 at one end thereof and fixed to a slidable member orstopper 290 at an opposite end thereof. The stopper 290 is disposed in acentral void or aperture 292 formed in the upper handle portion 276. Thescrew 288 is sized and shaped to mate with the inner thread 282 of therotatable lever 280 such that when the lever 280 is rotated a onequarter turn (ninety degrees) about the axis F in a clock-wise directionwhen viewed from the upper portion of the handle 276, the screw 288 ismoved from the position shown in FIG. 30 linearly upwardly along theaxis F to the position shown in FIG. 31. Such rotating action of thelever 280 also slides the stopper 290 upwardly in the aperture 292 to aposition abutting against an upper wall or stop 296, with a portion ofthe screw 288 also disposed in the aperture 294 as illustrated in FIG.31. The stop 296 prohibits any further upward movement of the screw 288,attached shaft 285 and attached driving tip 273, fully retracting thetip 273 into the housing 272. Likewise, when the driving tip 273 is inthe fully extended position shown in FIGS. 27 and 30, the stopper 290abuts against a lower wall or stop 298 that also defines the aperture294, prohibiting any further downward movement of the driving tip 273.

A pair of pins 299 fix the upper handle portion 276 to the lower handleportion 278 and capture the rotatable lever 280 therebetween. Asillustrated in FIG. 32, the lever 280 further includes inner curvedchannels 300, with the pins 299 received in and extending therethrough.The channels 300 are sized and shaped to allow the lever 280 toslidingly rotate the one quarter turn or ninety degrees required forextending and retracting the driving tip 273 as previously describedherein, but prohibiting any additional rotation of the lever 280 ineither direction.

Although not shown in the drawings, it is foreseen that the handle lowerportion 278 may be imprinted or otherwise marked with the words “UP” and“DOWN” on a surface 302 thereof to reveal to the surgeon whether thedriving tip 273 is extended or retracted. With respect to theillustrated embodiment, when the lever 280 is positioned over andcovering the word “UP,” the word “DOWN” would be uncovered and visiblewhen the tool 18 is in the position shown in FIG. 30. After rotating onequarter turn as shown in FIG. 31, the lever 280 would be positioned overand covering the word “DOWN,” leaving the word “UP” uncovered andvisible to the surgeon. As illustrated in FIG. 34, the driving tiphousing 272 provides adequate space about the driving tip 273 to allowfor full retraction of the tip 273 into the housing 272. Specifically,the housing 272 forms a void or channel 304 sized and shaped to receivethe driving tip 273 in the retracted position.

The driving tip 273 is substantially cylindrical and has a centralthrough slot 306 and facets for capturing and holding the closurestructure 28 prior to and during insertion in the receiver 26. The tip273 further includes a lateral projection or key 308 sized and shaped tomate with the key slot 116 of the closure structure 28 for precisepositioning of the closure structure 28 into the insertion tool 14 andthe receiver 26 by the reduction tool 18. Specifically, the outer thread268 formed on the reduction tool 18 is sized and shaped to rotatablymate with the thread 168 of the insertion tool 14. Furthermore aposition of a leading surface 310 of the thread 268 and the leadingsurface 170 of the thread 168 are synchronized along with thepositioning of the key 308 of the driving tip 273 so that a controlled,exact mating of the closure 28 with the receiver 26 is consistentlyaccomplished. Finally, both the reduction tool 18 and the insertion tool14 are sized and shaped such that the closure structure 28 is advancedtill snug, but cannot be driven past the top surfaces 74 and 75 of thereceiver 26, with a thread run-out portion 312 on the reduction tool 18configured and positioned to stop rotation of the thread 268 withrespect to the thread 168 of the insertion tool 14, prohibiting anyfurther rotation or downward motion of the tool 18 with respect to thetool 14. The reduction tool 18, in cooperation with the insertion tool14, provides apparatus for moving the cord 6 of the longitudinalconnecting member 3 (or other type of connecting member, such as a coilor rod) downwardly in a controlled manner into the receiver 26 byrotating the reduction tool 18, and also thereby precisely mating thethread 268 with the guide and advancement structure 168, capturing thecord 6 or other longitudinal connecting member within the receiver 26.

With reference to FIG. 36, the closure starter 20 for use in methods ofthe invention includes a handle 320 fixed to an elongate cylindricalstem or shaft 322 and a driving tip 324 integral to the shaft 322. Thehandle 320, shaft 322 and tip 324 are coaxial along an axis of rotationG. The handle 320 includes shallow apertures 326 to aid a surgeon ingripping and rotating the starter 20 about the axis G when the starter20 is engaged with a closure structure 28. The closure starter 20 issized and shaped to be used in cooperation with the insertion tool 14,with the tip 324 in engagement with a closure structure 28 and thestarter 20 extending through the tool 14 with the handle 320 locatedabove the lock pins 120 to allow for adequate clearance between thehandle 320 and the insertion tool 14 to allow for the rotation of theclosure structure 28 into the receiver 26 by turning the handle 320. Thedriving tip 324 includes a slot and faceted geometry for capturing andholding the closure structure 28 prior to and during insertion of thestructure 28 into the receiver 26. The closure starter 20 is usefulwhen, as shown in FIG. 36, the cord 6 or other longitudinal connectingmember has been previously reduced into the receiver 26 such that thereduction tool 18 is not required.

In use, the previously described tools are utilized to attach one ormore longitudinal connecting member 3 to the human spinal column 12. Theprocedure is begun by selection of a bone screw 1 in accordance with thesize of the patient's vertebra 10 and the requirements of the spinalsupport needed. The illustrated hinged bone screws 1 are preferred foruse with the cord 6 and spacers 8 of the illustrated longitudinalconnecting member 3. The hinged screw 1 advantageously allows for aplurality of angular or articulated locking positions between the shank24 and the receiver 26. Also with respect to the cooperation betweenbone screws and the cord 6 and spacers 8 of the longitudinal connectingmember 3, an advantage of both fixed screws and the hinged screw 1 overpolyaxial bone screws is that the hinged or fixed screws maintain a setor constant distance between receivers that aids in keeping the cord 6in a desired tension. Fixed bone screws as illustrated in FIGS. 40-49,an alternative hinged bone screw illustrated in FIGS. 52-54 and analternative polyaxial bone screw illustrated in FIG. 55, are alsodescribed more fully below that may be utilized with tools according tothe invention to attach one or more longitudinal connecting members 3 toa human spine 12. Furthermore, as will be described more fully below,other types of longitudinal connecting members may also be usedaccording to the invention including rods and coils. Bone screwsaccording to the invention are also preferably cannulated so as to bereceivable over and guided by a guide pin or wire 330 as discussed morefully below.

With particular reference to FIGS. 1, 6 and 7, a hinged bone screw 1 ofthe invention may be assembled by up or bottom loading the bone screwshank 24 into the receiver 26 with the side surfaces 62 facing the innerside walls 107 of the receiver 26. The shank 24 is uploaded until theend portion 38 abuts against the upper wall surfaces 106. Thereafter,the shank 24 is rotated about the axis A about ninety degrees, followedby lowering the end portion 38 until the lowered curved surfaces 57 ofthe wing projections 56 contact the lower seat 78 of the receiver 26 atthe locking teeth 80.

With particular reference to FIGS. 10-23, the insertion tool 14 may beplaced into engagement with the hinged bone screw 1 as follows: The bonescrew receiver 26 that has been attached to a shank 24 as previouslydescribed herein is first aligned with an insertion tool 14 by aligningthe laser etched stripe 98 of the receiver with the laser etched stripe100 of the insertion tool 14. Such alignment places the side 144 of theinsertion tool 14 and the side 72 of the receiver 26 facing in the samedirection and the through channel 148 communicating and aligned with theU-shaped channel 76 of the receive 26. The upper extension 216 of thelock pin driver 210 may then be inserted into the channel 148 with theopposed planar sides 217 being received in the channel 148. The lock pindriver 210 is then rotated about its axis D causing the opposed curvedsides 218 to abut against the surfaces forming the channel 148 to spreadthe tangs 128 and 129 apart, followed by inserting the tool 14 onto thebone screw receiver 26 outer arm surfaces 72 and 73 at a location spacedfrom the top surfaces 74 and 75. The lock pin driver 210 is rotatedagain, thereby releasing the tool 14 from the curved surfaces 218 andthus snapping the tool 14 onto the receiver 26. Thereafter the lock pinextension 216 is removed from the through channel 148 and the insertiontool 14 is pulled upwardly and away from the receiver 26, the tool 14sliding upwardly along the inwardly sloping surfaces 88 and 89 leadingup to the undercut grooves 86 and 87 until the projections 186 and 187are received and engaged with the receiver 26 at the respective grooves86 and 87. Such engagement results in a firm attachment that alsoresists any attempt to spread or splay the tangs 128 and 129. Also, theraised strip 194 of the tool 14 is received in the slit 94 of thereceiver and the raised strip 195 of the tool 14 is received in the slit95 of the receiver. The raised strips 194 and 195 also extend upwardlyfrom the top surfaces 74 and 75 of the receiver 26 as illustrated inFIG. 23.

With particular reference to FIGS. 19 and 23, a pair of lock pins maythen be inserted in the insertion tool 14 cylindrical channels 158 and162 with each lock pin tip or bottom 202 being inserted into thechannels at the top surface 134 and guided downwardly toward the bottom136 of the tool 14. Once the threaded portion 206 makes contact with thethreaded inner wall 160 or 164, the lock pin 120 is rotated and drivendownwardly toward the receiver surface 74 or 75 by mounting the lock pindriver 210 on a lock pin 120 with the driving portion 204 of the pin 120received in the elongate socket 222 and the top 200 of the pin 120abutting against and frictionally engaging the top surface or stop 224.The lock pin driver 210 is rotated about the axis D until the bottomsurface 202 frictionally engages with the receiver surfaces 74 or 75.With respect to the pin 120 abutting the surface 74, the raised strip194 prohibits movement of the pin 120 toward the receiver side surface92. With respect to the pin 120 abutting the surface 75, the raisedstrip 195 prohibits movement of the pin 120 toward the opposite receiverside surface 93. Thus the two strips 194 and 195 cooperate to preventfront to back movement of the insertion tool 14 between the receiverside surfaces 92 and 93.

With reference to FIGS. 24-26 and 37, after installation of theinsertion tool 14 on the bone screw receiver 26, the driver 16 isinserted into the insertion tool 14 by inserting the driving end 234into the lateral opening 149 of the longitudinal channel 132 near thetop 134 of the tool 14 with the shaft 232 being received in the narrowchannel 152, followed by sliding the shaft 232 downwardly along the axisC into the interior of the tool 14 with both the alignment tab 238 andthe centering tab 240 aligned with and then passing into the narrowchannel 152 at the front 140 of the alignment tool 14. By aligning thetabs 238 and 240 with the front 140 of the tool 14, the driving end 234of the driver 16 is set up for proper engagement with the receiver 26and the end portion 38 of the shank 24. The tab 240 is then passedthrough the narrow channel 152 and into the through channel 148. Oncethe tab 238 enters the channel 152 and is fully received thereby, thedriving end lower surface 244 engages the top surface 60 of the endportion 38 of the shank 24 and the lower seat 78 of the receiver 26. Thedriving end 234 also contacts the receiver 26 along an entire height ofthe U-shaped channel 76 from the lower seat 78 to the upper surfaces 74and 75. The driver 16 is now in position to drive the bone screw 1 intoa vertebra 10 as illustrated in FIG. 37. The alignment tab 238cooperating with and engaging the surfaces forming the channel opening152 and the centering tab 240 cooperating with and engaging the frontface 172 of the tool 14 keep the driving end 234 in proper position,fully engaging the receiver 26 as the driver 16 is manually rotatedabout the axis E to rotate and drive the bone screw 1 into the vertebra10 as will be described more fully below. Thereafter, the driver 16 maybe removed by simply sliding the shaft 232 upwardly along the axis C andthen laterally out of the tool 14 through the upper side opening formedby the channel 152, with the driving end 234 being easily removable outof the squared off opening 149 of the upper portion of the channel 148.

With particular reference to FIGS. 37-39, a relatively minimallyinvasive incision or incisions are made and stretched so as to snuglyreceive the tools of the invention. A drill (not shown) is utilized toform a first guide bore in a vertebra 10 under guidance of non invasiveimaging techniques, which procedure is well known and established. Athin pin or guide wire 330 is then inserted in the first guide bore, thepin and guide bore functioning to minimize stress on the vertebra 10 andproviding an eventual guide for the placement and angle of the bonescrew shank 24 with respect to the vertebra 10. Then the guide bore isenlarged utilizing a cannulated drilling tool or tap having an integralor otherwise attached cannulated and threaded bit with an outer surfacesized and shaped to correspond to the size and shape of the chosenthreaded bone screw 1.

With the pin 330 fixed to the vertebra 10 and in place in an enlargedguide bore 332 and extending upwardly through the bore and out of theincision, the pin 330 is threaded into the bore 66 at the tip 44 of theshank 24 and out of the opening at the top surface 66 of the bone screwshank 24. The pin 330 is then threaded into the driver 16 at the bore248 opening at the surface 244 and then up through the bore 248 of thedriver 16. Care is taken to insure that the axis A of the bone screwshank 24 is aligned and coaxial with the axis B of the receiver when thedriver 16 driving end 234 engages the top surface 60 of the bone screwshank 24. Thereafter, driver contact with the surface 60 of the shank 24maintains coaxial alignment of the shank and receiver during driving ofthe shank body 36 into the vertebra 10. With the driver 16 installed onthe insertion tool 14 properly aligned as illustrated in FIG. 37 and aspreviously described herein, the bone screw 1 is then rotated and driveninto the tapped bore 332 in the vertebra 10 with the surgeon holding androtating the bone screw assembly 1 and the insertion tool 14 with thedriver handle 230 until the shank body 36 is disposed at a desired depthin the tapped bore 332 of the respective vertebra 10.

With reference to FIG. 39, at least two and up to a plurality of bonescrews 1 with attached insertion tools 14 are installed in each vertebra10 to be attached to the longitudinal connecting member 3. After aspecific bone screw 1 is installed, the driver 16 is removed by slidingthe shaft 232 up through the open top 134 of the tool 14, out of theside opening and away from the bone screw 1 and the attached insertiontool 14.

With reference to FIGS. 38 and 39, the reduction tool 18 is then used topress the longitudinal connecting member 3 or other type of longitudinalconnecting member, such as a rod or coil, downwardly into the receivers26 of the implanted bone screws 1. In the embodiment shown, a spacer 8is cut to length and pre-loaded onto a cord 6 then the cord 6 of thelongitudinal connecting member 3 is inserted into and through a throughbore 148 of an insertion tool 14 with a tail or end 334 of the cord 6extending out of the bore 148. The other end of the cord 6 is theninserted into a through bore 148 of an adjacent insertion tool 14,followed by the threading of another spacer 8, with such processcontinuing until a threaded spacer 8 of appropriate length is disposedbetween each of the insertion tools 14 with the cord extending througheach through bore 148, either above or below the patient's skin. Thenall of the spacers 8 are pressed downwardly through the incision andgenerally between the insertion tools 14 and near the bone screwreceivers 26.

Prior to engagement with an insertion tool 14, the reduction tool 18 isattached to a closure structure 28 as follows: The reduction tool 18driving tip 273 is placed in an extended, closure structure engagingposition as shown in FIG. 27 by rotating the lever 280 one quarter turnin a clock-wise direction, if necessary, to fully expose the tip 273.The closure structure 28 is then placed on the driving tip 273 with thetip 273 fully engaging the internal drive socket 115 and the laterallyprojecting key 308 being received in the key slot 116, the driving tip273 surfaces and key 308 frictionally holding the closure structure 28on the driving tip 273 as the structure 28 is inserted into the openlongitudinal channel 132 through the side opening 149 near the upper endor top 134 of the tool 14, the reduction tool lower shaft housing 270being received in the narrow channel 152. The closure structure 28 andattached reduction tool housing portions 266, 270 and 272 are thenslidingly received and lowered in the longitudinal channel 132 along theaxis C until the threaded portion 268 of the tool 18 makes contact withthe guide and advancement structure 168 disposed near the top of theinsertion tool 14.

With particular reference to FIG. 38, the reduction tool 18 is thenrotated about the axes C and F by rotating the handle 260 to move theclosure structure 28 toward the receiver 26 in a controlled manner.During such rotation, the closure structure bottom surface 113 makescontact with the cord 6 and presses the cord 6 downwardly and toward andinto the channel 76 of the receiver 26. As previously stated herein, thestarting locations 170 and 310 of the respective mating guide andadvancement structures 168 and 268, as well as the key 308 on thedriving tip 273 and the key slot 116 on the closure structure 28 are allpositioned to precisely mate the closure structure guide and advancementstructure 110 with the receiver guide and advancement structure 82.Furthermore the guide and advancement structures 168 and 268 are sizedand positioned such that once the closure structure 28 is threaded fullyinto the receiver 26 with the top surface 112 of the closure structure28 being flush with the top surfaces 74 and 75 of the receiver 26,further rotation of the tool 18 may be prohibited by abutment of theguide and advancement structure 168 with an optional thread run out stop312 on the reduction tool 18. At such time, the cord 6 is captured inthe receiver 26 and the closure structure 28 may or may not be fullytightened and torqued within the receiver 26.

The driving tip 273 of the reduction tool 18 is then retracted byrotating the lever 280 of the handle 260 in a counter-clockwisedirection one quarter turn, detaching the driving tip 273 from theclosure structure 28, thereby deploying it. The reduction tool 18 maythen be removed from the insertion tool 14 by rotating the handle 260 ina counter-clockwise direction to move the tool 18 upwardly and away fromthe receiver 26. Once the guide and advancement structure 268 isdisengaged from the guide and advancement structure 168, the tool 18 maybe pulled up and slid sideways out of the tool 14.

With reference to FIG. 39, in order to install a longitudinal connectingmember 3 in two or more bone screws 4, it may or may not be necessary toequip each insertion tool 14 with a reduction tool 18. It may besufficient to utilized the reduction tool 18 with only one insertiontool 14, for example the bone screw receiver 26 and attached insertionguide tool 14 shown in both FIGS. 38 and 39 located at an end of a groupof bone screws, shown having a tail 334 of the cord 6 extendingtherefrom. Thereafter, the closure structures 28 may be placed in theremaining receivers 26 utilizing the closure starter 20.

The closure starter 20 may be used similarly to the reduction tool 18,with the closure structure 28 first placed on the tool 20 with thedriving tip 324 engaging the internal drive socket 115, the driving tip324 surfaces and slot holding the closure structure 28 on the drivingtip 324 as the structure 28 is side-loaded into the longitudinal channel132 of the tool 14 with the driving tip 324 and attached structure 28inserted into the lateral opening 149 of the tool 14 and a lower portionof the shaft 322 being received in the narrow channel 152 formed nearthe top of the tool 14. The closure structure 28 and attached closurestarter shaft 322 are then slidingly received in the channel 132 alongthe axis C until the guide and advancement structure 110 of the closurestructure 28 makes contact with the guide and advancement structure 82of the receiver 26. The closure starter 20 is then rotated about theaxis G by rotating the handle 320 to rotate and drive the closurestructure 28 into the receiver 26. During such rotation, the closurestructure bottom surface 113 contacts the cord 6 and presses the cord 6into the channel 76 of the receiver 26. At such time, the cord 6 iscaptured in the receiver 26. The closure structure 28 may or may not befully tightened and torqued within the receiver 26. For removal, theclosure starter 20 is simply moved upwardly and away from the receiver26 and then out of the insertion tool 14.

Once all of the closure structures 28 are in a seated position inrespective bone screws 1 and the surgeon is satisfied with the positionof all of the elements, the structures 28 may be locked into place withan elongate driving or torquing tool having a driving tip similar oridentical to the reduction tool 18 driving tip 273 or the closurestarter 20 driving tip 324 as well as an elongate shaft sized and shapedto be slidingly received in the insertion tool 14. Such a torquing tooltypically includes a T-shaped handle to aid the surgeon in applyingadequate tightening force, typically 70-120 inch pounds, to fullytighten and set the closure structure 28 within the receiver 26 so thatthe surface 113 is snug against the cord 6. An anti-torque holding toolmay be utilized to hold the insertion tool 14 during tightening with thetorquing tool. Such an anti-torque holding tool is also elongate andincludes a hollow shaft sized and shaped to slidingly mate over theinsertion tool 14. Therefore, such an anti-torque holding tool would besubstantially rectangular in cross-section, sized and shaped to closelyfit about the insertion tool 14, and include a handle for holding theinsertion tool 14 in place during rotation of the torquing tool, therebyallowing a surgeon to counter the torque applied by the insertion tool14 when applying torque to the closure structure 28. The antitorque tooltypically also has an upper handle with an opening through which thetorquing tool passes. Although designed for use with a cylindricalinsertion tool, the torquing tool and anti-torque tool combinationillustrated in U.S. patent application Ser. No. 10/789,149, filed Feb.27, 2004 may be instructive here, the disclosure of which isincorporated by reference herein. Furthermore, a cord tensioninginstrument as is known in the art is used to place tension on the cord 6as each closure structure 28 is torqued and tightened.

After all of the closure structures 28 have been locked into place andthe cord 6 adequately tightened, each of the insertion tools 14 areremoved by mounting the lock pin driver 210 onto each lock pin 120 andloosening each of the pair of pins 120 from the insertion tool 14 byrotating the driver 210 in a counter-clockwise direction. Each pin 120is then rotated upwardly and away from the tool 14. Downward force isthen placed on the insertion tool 14 by the surgeon to move the implantengaging members or projections 186 and 187 out of the grooves 86 and 87of the receiver 26. Then the lock pin driver upper extension 216 isinserted into the channel 148 with the opposed planar sides 217 beingreceived in the channel 148. The lock pin driver 210 is then rotatedabout its axis D causing the opposed curved sides 218 to abut againstthe surfaces forming the channel 148 to spread the tangs 128 and 129apart, followed by removing the tool 14 from the bone screw receiver 26outer arm surfaces 72 and 73 and axially upwardly away from the receiver26. The lock pin driver 210 is rotated again, thereby releasing the tool14 from the curved surfaces 218. Thereafter the lock pin extension 216is removed from the through channel 148 and the insertion tool 14 ispulled away from the bone screw 1 and out of the incision 350. Suchprocedure is followed to remove each insertion tool 14 out of theincision.

With reference to FIGS. 40-42 an alternative open fixed bone screwgenerally 340 according to the invention and for use with the tools 14,16, 18 and 20 of the invention includes a receiver 342 fixed to a shank344. The bone screw 340 is substantially similar to the bone screw 1with the exception that the fixed shank 344 cannot be articulated withrespect to the receiver 342 and is thus in fixed substantially coaxialrelationship therewith.

Similar to the shank body 36 of the bone screw 1, the shank 344 of thebone screw 340 is elongate, having a helically wound, radially outwardlyextending bone implantable thread 346 axially extending from near alower end or tip 348 of the body 346 to near the receiver 342. Toprovide a biologically active interface with the bone, the threadedshank 344 is coated, perforated, made porous or otherwise treated 350.The treatment 350 may include, but is not limited to a plasma spraycoating or other type of coating of a metal or, for example, a calciumphosphate; or a roughening, perforation or indentation in the shanksurface, such as by sputtering, sand blasting or acid etching, thatallows for bony ingrowth or ongrowth. Certain metal coatings act as ascaffold for bone ingrowth. Bio-ceramic calcium phosphate coatingsinclude, but are not limited to: alpha-tri-calcium phosphate andbeta-tri-calcium phosphate (Ca₃(PO₄)₂, tetra-calcium phosphate(Ca₄P₂O₉), amorphous calcium phosphate and hydroxyapatite(Ca₁₀(PO₄)₆(OH)₂). Coating with hydroxyapatite, for example, isdesirable as hydroxyapatite is chemically similar to bone with respectto mineral content and has been identified as being bioactive and thusnot only supportive of bone ingrowth, but actively taking part in bonebonding. In the illustrated embodiment, the shank 344 is cannulated witha small central bore 352 extending an entire length of the shank. Thebore 352 is coaxial with the threaded body 344 and opens at the tip 348and also at a curved seating surface 354, providing a passage throughthe shank interior for a length of wire or pin inserted into thevertebra 10 prior to the insertion of the shank 344, the wire or pinproviding a guide for insertion of the shank body 344 into the vertebra10.

The receiver 342 includes a base 356 integral with a pair of opposedupstanding arms 358 and 359 that extend from the base 356 to respectivetop surfaces 360 and 361. The arms 358 and 359 form a U-shaped cradleand define a U-shaped channel 364 between the arms 358 and 359 andinclude an upper opening 365 and the lower seating surface 354. Thelower seating surface 354 is sized and shaped to engage the cord 6 ofthe longitudinal connecting member 3 previously described herein. Eachof the arms 358 and 359 has an interior surface that defines an innercylindrical profile and includes a discontinuous helically wound guideand advancement structure 366. In the illustrated embodiment, the guideand advancement structure 366 is a partial or discontinuous helicallywound flangeform configured to mate under rotation with the guide andadvancement structure 110 on the closure structure 28, as similarlypreviously described herein with respect to the bone screw 1. However,it is foreseen that the guide and advancement structure 366 couldalternatively be a buttress thread, a square thread, a reverse anglethread or other thread like or non-thread like helically woundadvancement structure for operably guiding under rotation and advancingthe closure structure 28 downward between the arms 358 and 359 andhaving such a nature as to resist splaying of the arms 358 and 359 whenthe closure 28 is advanced into the U-shaped channel 364.

Each of the arms 358 and 359 has a substantially planar outer surface370 and 372, respectively, that includes a substantially linear undercuttool engagement groove 374 and 375, identical to the tool engagementgrooves 86 and 87 described previously herein with respect to the bonescrew 1 that are sized and shaped to engage the insertion tool 14projections 186 and 187. Further, offset opposed insertion tool engagingslits 378 and 379 are identical to the slits 94 and 95 describedpreviously herein with respect to the bone screw 1. The side 370 furtherincludes a laser etched stripe 380 for alignment with the similar stripe100 on the tool 14, also as previously described herein with respect tothe bone screw 1. Opposed front and back surfaces 382 and 383,respectively, are both substantially planar and parallel.

As illustrated in FIG. 50, when two bone screws 340 of the invention areutilized that have planar parallel front and back surfaces 382 and 383,the opposed sides 9 of the spacer 8 may need to be cut or otherwisesized to be non-parallel in order to create or preserve spinal lordosisor kyphosis. In the embodiment illustrated in FIG. 50 the spacer 8 hassubstantially trapezoidal opposing sides 385 to create or preservespinal lordosis at one or more motion segments.

The bone screw 340 cooperates with the insertion tool 14 and thereduction tool 18 in a manner identical to the cooperation between thebone screw 1 and such tools as previously described herein. With respectto the bone screw driver 16, the receiver portion forming the U-shapedchannel 364 and the lower seat 354 cooperate with the driver 16 in amanner similar to the cooperation between the receiver 26 portionforming the U-shaped channel 76 and the lower seat 78 and upper surface60 of the hinged shank 24.

With reference to FIGS. 43-46, additional alternative open fixed screwsaccording to the invention are illustrated that include receivers havingopposed surfaces for creating or preserving spinal lordosis or kyphosis.Rather than modifying the spacer 8 as illustrated in FIG. 50, such bonescrews allow for the use of a standard or consistent spacer 8 withparallel sides surfaces 9, with the bone screw receiver being shaped tocompensate for or create spinal lordosis or kyphosis at one or moremotion segments.

FIGS. 43 and 44 illustrate open fixed bone screws 387 and 388,respectively, having respective “lordosing” receiver opposed surfaces390 and 391. And FIGS. 45 and 46 illustrate open fixed bone screws 393and 394 respectively, having respective “kyphosing” receiver opposedsurfaces 396 and 397. With the exception of the opposed side surfaces390, 391, 396 or 397, the respective bone screws 387, 388, 393 and 394are substantially identical to the bone screw 340 previously describedherein and such discussion is incorporated by reference with respect tothe screws 387, 388, 393 and 394. Therefore the bone screws 387, 388,393 and 394 all fully cooperate with each of the tools 14, 16, 18 and 20as previously described herein with respect to the bone screw 340 andalso the bone screw 1.

With respect to the bone screws 387 and 388 illustrated in FIGS. 43, 44and 51, the “lordosing” pair of opposed surfaces 390 and pair of opposedsurfaces 391 each define receivers with lateral trapezoidal profiles,that are wider at the bottom than at the top of the receiver, so thatwhen a pair of such bone screw receivers are compressed against opposedparallel sides 9 of a spacer 8, the bone screw shanks will diverge,thereby creating or preserving lordosis, as illustrated in FIG. 51. Ascan be seen in the drawings, the bone screws 390 and 391 differ from oneanother only in the angle or degree of upward convergence of the sides390 or the sides 391, corresponding to a degree of segmental lordosisoccurring or desired in a patient's spine. For example, the bone screw387 corresponds to about ten degrees lordosis while the bone screw 388corresponds to about five degrees lordosis. It is foreseen that otherbone screws according to the invention may be made that result ingreater or lesser degrees of lordosis. Furthermore, it is noted that,for example, three or more bone screws 387 may be implanted in adjacentvertebrae resulting in a greater regional lordosis, for example, offorty degrees or more.

With respect to the bone screws 393 and 394 illustrated in FIGS. 45 and46, the “kyphosing” pair of opposed surfaces 396 and pair of opposedsurfaces 397 each define receivers with inverted lateral trapezoidalprofiles, that are wider at the top than at the bottom of the receiver,so that when a pair of such bone screw receivers are compressed againstopposed parallel sides 9 of a spacer 8, the bone screw shanks willconverge, thereby creating or preserving segmental or regional kyphosis.As can be seen in the drawings, the bone screws 393 and 394 differ fromone another only in the angle or degree of upward divergence of thesides 393 or the sides 394, corresponding to a degree of kyphosisoccurring or desired in a patient's spine. For example, the bone screw393 corresponds to about five degrees kyphosis while the bone screw 394corresponds to about ten degrees kyphosis. It is foreseen that otherbone screws according to the invention may be made that result ingreater or lesser degrees of kyphosis. Also, it is foreseen that up to aplurality of kyphosing screws 393 and 394 may be used to create orpreserve a greater amount of regional kyphosis.

With reference to FIGS. 47-49, alternative lordosing and kyphosingclosed bone screws according to the invention are illustrated. Withreference to FIG. 47, a kyphosing closed bone screw, generally 401,includes a receiver 404 having a closed inner channel for receiving acord 6 of a longitudinal connecting member 3 therethrough. The receiver404 is fixed to a threaded shank 406 for implantation into a vertebra10. The receiver 404 includes opposed upwardly diverging surfaces 408defining an inverted lateral trapezoidal profile that is wider at thetop than at the bottom of the receiver 404, so that when the receiver494 is compressed against parallel sides 9 of a spacer 8, adjacent bonescrew shanks 406 will converge, thereby creating or preserving kyphosis.The receiver 404 corresponds to about ten degrees kyphosis. It isforeseen that other closed bone screws according to the invention may bemade that result in greater or lesser degrees of kyphosis. Also, it isforeseen that up to a plurality of kyphosing screws 401 may be used tocreate or preserve a greater amount of regional kyphosis.

With reference to FIGS. 48 and 49, closed lordosing screws generally 410and 411, respectively, are illustrated. Both of the screws 410 and 411have respective receivers 414 and 415, that are each fixed to a bonescrew shank similar or identical to the shank 406. Each receiver 414 and415 has a closed inner channel for receiving a cord 6 of a longitudinalconnecting member 3 therethrough. The receivers 414 and 415 haverespective “lordosing” opposed surfaces 418 and opposed surfaces 419,that define lateral trapezoidal profiles, that are wider at the bottomthan at the top of the receiver, so that when a pair of such bone screwreceivers are compressed against opposed parallel sides 9 of a spacer 8,the bone screw shanks will diverge, thereby creating or preservinglordosis. As can be seen in the drawings, the bone screws 410 and 411differ from one another only in the angle or degree of upwardconvergence of the sides 418 or the sides 419, corresponding to a degreeof lordosis occurring or desired in a patient's spine. For example, thebone screw 418 corresponds to about five degrees lordosis while the bonescrew 419 corresponds to about ten degrees lordosis. It is foreseen thatother bone screws according to the invention may be made that result ingreater or lesser degrees of lordosis. Furthermore, it is noted that,for example, three or more bone screws 411 may be implanted in adjacentvertebrae resulting in a greater regional lordosis, for example, offorty degrees or more.

With reference to FIGS. 52-54, the reference numeral 430 generallydesignates an alternative hinged bone screw assembly according to theinvention for cooperation with the dynamic stabilization connectingmember 3 or other longitudinal connecting members including, but notlimited to solid and hollow rods and coil-like members. Similar to whathas been described previously herein with respect to the hinged bonescrew 1, the hinged bone screw 430 also cooperates with the closurestructure 28 and may be manipulated by using the insertion tool 14, thebone screw driver 16, the reduction tool 18 and the closure starter 20.

The hinged bone screw assembly 430 includes a shank 432, a receiver 434and an insert 435 for attaching the shank 432 to the receiver 434. Theshank 432 is substantially similar to the shank 24 of the assembly 1.Specifically, the shank 432 includes a body 436 integral with anupwardly extending end portion 438. The shank 432 and the receiver 434are assembled using the insert 435 prior to implantation of the shankbody 436 into the vertebra 10. The shank 432 of the bone screw assembly430, is elongate, having an axis of rotation R. The shank body 436 has ahelically wound, radially outwardly extending bone implantable thread440 axially extending from near a lower end or tip 444 of the body 436to near a slanted or sloped surface 446 that is adjacent to a smoothsubstantially cylindrical surface 448 located adjacent to the endportion 438. During use, the body 436 utilizing the thread 440 forgripping and advancement is implanted into the vertebra 10 leading withthe tip 444 and driven down into the vertebra 10 with the driving tool16 so as to be implanted in the vertebra 10 to near the sloped surface446.

To provide a biologically active interface with the bone, an outersurface 450 of the shank body 36 that includes the thread 440 andextends between the surface 446 and the tip 444 is coated, perforated,made porous or otherwise treated 452. The treatment 452 may include, butis not limited to a plasma spray coating or other type of coating of ametal or, for example, a calcium phosphate; or a roughening, perforationor indentation in the surface 450, such as by sputtering, sand blastingor acid etching, that allows for bony ingrowth or ongrowth. Certainmetal coatings act as a scaffold for bone ingrowth. Bio-ceramic calciumphosphate coatings include, but are not limited to: alpha-tri-calciumphosphate and beta-tri-calcium phosphate (Ca₃(PO₄)₂, tetra-calciumphosphate (Ca₄P₂O₉), amorphous calcium phosphate and hydroxyapatite(Ca₁₀(PO₄)₆(OH)₂).

The sloped surface 446 extends radially inward and axially upward fromthe shank body 436 to the cylindrical portion 448. Further extendinglaterally outwardly from the cylindrical portion 448 is the upper endportion 438 that provides a connective or capture apparatus disposed ata distance from the threaded shank body 436 and thus at a distance fromthe vertebra 10 when the body 436 is implanted in the vertebra 10. Theupper end portion 438 is configured for connecting the shank 432 to thereceiver 434 and capturing the shank 432 in the receiver 434. The upperend portion 438 has a pair of projections or wings 456 that extendlaterally oppositely outwardly from the cylindrical surface 448. Eachprojection 456 has a lower curved, convex surface 457 shaped to engage aconcave seating surface of the receiver 434, to be described more fullybelow. The shank 432 is sized and shaped for top- or down-loading of theshank 432 into the receiver 434 as illustrated in FIG. 52, with theinsert 435 thereafter being received in the receiver 434 and engagingthe shank 432 at the cylindrical surface 448 and prohibiting upwardmotion of the shank 432 out of the channel opening 477. The upper or endportion 438 further includes a top surface 460 that includes a concaveportion sized and shaped for receiving and engaging the driver 16 andalso the cord 6. A side surface 462 extends between the top surface 460and each curved lower surface 457.

In the illustrated embodiment, the shank 432 is cannulated with a smallcentral bore 466 extending an entire length of the shank along the axisR. The bore 466 is coaxial with the threaded body 436 and opens at thetip 444 and the top surface 460, providing a passage through the shankinterior for a length of wire or pin inserted into the vertebra 10 priorto the insertion of the shank body 436, the wire or pin providing aguide for insertion of the shank body 436 into the vertebra 10.

The receiver 434 is substantially similar to the receiver 26 of theassembly 1, including a base 470 integral with a pair of opposedupstanding arms 472 and 473 that extend from the base 470 to respectivetop surfaces 474 and 475. The arms 472 and 473 form a U-shaped cradleand define a U-shaped channel 476 between the arms 472 and 473 andinclude an upper opening 477 and a lower seat 478. The lower seat 478 issized and shaped to cooperate with and frictionally engage the lowersurfaces 457 of the shank upper end portion 438. Each of the arms 472and 473 has an interior surface that defines an inner cylindricalprofile and includes a discontinuous helically wound guide andadvancement structure 482. In the illustrated embodiment, the guide andadvancement structure 482 is a partial or discontinuous helically woundflangeform configured to mate under rotation with a similar structure onthe substantially cylindrical closure structure 28 as previouslydiscussed herein with respect to the receive 26. However, it is foreseenthat the guide and advancement structure 482 could alternatively be abuttress thread, a square thread, a reverse angle thread or other threadlike or non-thread like helically wound advancement structures foroperably guiding under rotation and advancing a closure structuredownward between the arms 472 and 473 and having such a nature as toresist splaying of the arms 472 and 473 when the closure 28 is advancedinto the U-shaped channel 476.

Each of the arms 472 and 473 has planar outer surfaces, ledges, slitsand linear undercut tool engagement grooves 486 and 487 identical to theouter arm surfaces, ledges, slits and grooves 86 and 87, respectively,previously described herein with respect to the bone screw receiver 26.Such grooves and surfaces allow for easy, sliding engagement and releaseof the tool 14 from the bone screw receiver 434, identical to what hasbeen previously described herein with respect to the bone screw assembly1. The receiver arm 472 outer side surface further includes a centrallylocated laser or otherwise etched alignment stripe 488 running from nearthe groove 486 to near the receiver base 470. The stripe 488 is similarto the stripe 98 on the bone screw receiver 26 previously describedherein and cooperates with the similar stripe 100 on the insertion tool14 (illustrated in FIGS. 38 and 39), providing a visual aid and ease inthe alignment and proper attachment of the insertion tool 14 with thereceiver 434 by linearly aligning the stripe 488 with the stripe 100.The receiver 434 base 470 also has a laterally opening curved channel orslot 490 sized and shaped to slidingly receive the insert 435. Thelateral slot 490 communicates with the U-shaped channel 476 and alsowith a bottom curved slot 492 that also communicates with the U-shapedchannel 476 and opens to a lower exterior 494 of the receiver base 470.The laterally opening slot 490 is also sized and shaped to cooperatewith the bottom curved slot 492 to allow for hinged motion of the shank432 of about thirty degrees on either side of the axis R as partiallyillustrated in phantom in FIG. 53.

The insert 435 includes a concave upper surface 498A and a convex lowersurface 498B and further has a laterally opening U-shaped aperture orslot 499. The insert 436 is sized and shaped to be received in thecurved laterally opening slot 190 of the receiver 434 with the aperture499 receiving the cylindrical surface 448 of the shank 432.

To assemble the bone screw 430, the shank 432 is top- or down-loadedinto the receiver 434 tip 444 first into the channel upper opening 477with the wings 456 of the end portion 438 directed towards the openingsof the U-shaped channel 476 as illustrated in FIG. 52. The shank 432 ismoved downwardly until the wings 456 abut against the lower seat 478defining the U-shaped channel 476 of the receiver 434. Then, the insert435 is slid into the slot 490 until the cylindrical surface 448 isreceived in and engaged with the insert 436 at the U-shaped aperture499. As illustrated in FIG. 53, the shank 432 freely moves within thereceiver 434 through the axis R and in a plane that includes both thearms 472 and 473. The hinged motion of the shank body 436 is limited bythe bottom curved slot 492. When force is placed on the upper shanksurface 460, the shank end portion 438 frictionally engages the lowerseat 478 of the receiver 434 compressing the lateral slot 490 such thatthe receiver surfaces defining the slot 490 frictionally engage theinsert 435 at the top surface 498A thereof and also at the bottomsurface 498B thereof, locking the shank body 436 into an angularposition with respect to the receiver 434.

With reference to FIG. 55 an alternative polyaxial bone screw, generally501 of the invention and an alternative longitudinal connecting member,generally 505, for use in the invention, are illustrated. The polyaxialbone screw 501 includes a shank 508, a receiver 510 and a retaining andarticulating structure 512. The shank 508 further includes a threadedshank body 516 and an integral shank upper portion 518. The illustratedreceiver 510 includes tool attachment structure generally, 520 forcooperating and engaging with the insertion tool 14 identical to theattachment structure disclosed previously herein with respect to thereceiver 26 of the bone screw assembly 1, including, but not limited tothe grooves 86 and 87 and cooperating slits 94 and 95, such that theinsertion tool 14, the reduction tool 18 and the closure starter 20 maybe properly aligned and engaged with the closure structure 28 which inturn engages the receiver 510, with some modification to such tools, ifnecessary, to allow for cooperation with different types of longitudinalmembers. Furthermore, a modified driving tool (not shown) for rotatingand driving the bone screw 501 into a vertebra, similar to the drivingtool 16, includes alignment and centering tabs for engagement with theinsertion tool 14, but also includes a driving socket for engagementwith the bone screw shank upper portion 518 in lieu of the driving end234.

The illustrated receiver 510 is further sized and shaped to cooperateand engage with the closure structure 28 previously described herein orother suitable bone screw closure structure. The bone screw 510 isdescribed in greater detail in U.S. Provisional Application 60/728,912filed Oct. 21, 2005, the disclosure of which is incorporated herein byreference. Another bone screw assembly for use with longitudinalconnecting members, insertion tools and reduction tools of the presentinvention is described in U.S. Provisional Application 60/725,445, filedOct. 11, 2005, the disclosure of which is also incorporated by referenceherein. In the '445 application, the illustrated bone screw assemblyfurther includes upper and lower compression structures sized and shapedto engage an outer coil-like member, but not an inner cylindrical rodcore that is free to slide within the coil-like member, the upper andlower compression structures preventing the coil-like member frompressing or crushing against the inner cylindrical core.

The illustrated longitudinal connecting member 505 cooperates with twoor more bone screws 501 and is a non-fusion dynamic stabilizationlongitudinal connecting member assembly having an outer, cannulatedcoil-like connecting member 530 and one or more threaded inserts 532.The member 505 is described in detail in U.S. Provisional Application60/728,912, filed Oct. 21, 2005, the disclosure of which is incorporatedby reference herein. Furthermore, a dynamic fixation assembly with acoil-like member similar to the member 530 and having a single elongatethreaded core is described in U.S. Provisional Application 60/736,112filed Nov. 10, 2005, the disclosure of which is incorporated byreference herein. Also according to the invention, a solid cylindricalcore or insert (not shown) may replace the insert 532 and be attached tothe core at only one end thereof and be slidingly receivable within thecore along a substantial or entire length of the coil-like member 530.Such an embodiment is illustrated and described in U.S. ProvisionalApplication 60/725,445 filed Oct. 11, 2005, the disclosure of which isincorporated by reference herein. Furthermore, longitudinal connectingmembers made from solid rods or rods having solid or substantiallyhollow portions of non-uniform cross-section may be used with bone screwassemblies and tools according to the invention. Examples of suchconnecting members are described in U.S. Provisional Application60/722,300 filed Sep. 30, 2005, the disclosure of which is incorporatedby reference herein.

It is to be understood that while certain forms of the present inventionhave been illustrated and described herein, it is not to be limited tothe specific forms or arrangement of parts described and shown.

The invention claimed is:
 1. A bone screw assembly comprising: a receiver having an upper portion configured to receive a rod, a cavity and a base with a lower opening defined in the base and communicating with the cavity; a shank having a body, a longitudinal axis, and an upper end portion integral with the body, the integral upper end portion includes a drive structure positioned at least partially along the longitudinal axis and configured to receive a drive tool; the shank being configured so as to be bottom loadable into the receiver with the upper end portion inserted through the lower opening and positionable into the cavity; wherein upon the upper end portion of the shank being positioned into the cavity of the receiver, the receiver is configured to capture the upper end portion of the shank in a seated orientation thereby restricting a hinged motion of the shank body to a single plane with respect to the receiver, and wherein the receiver is configured to be removable from the upper end portion of the shank after the upper end portion of the shank is positioned in the cavity through the lower opening into the seated orientation and prior to the rod and a closure being positioned in the receiver.
 2. The bone screw assembly of claim 1, wherein the upper end portion of the shank is positionable in the cavity in a loading orientation with the upper end portion of the shank disposed at an upper portion of the cavity.
 3. The bone screw assembly of claim 2, wherein the receiver is configured to be removable from the shank in the loading orientation wherein the upper end portion of the shank is passable from the cavity to a lower exterior of the receiver.
 4. The bone screw assembly of claim 1, wherein the seated orientation comprises the upper end portion of the shank disposed at a lower portion of the cavity.
 5. The bone screw assembly of claim 4, wherein the seated orientation further comprises the upper end portion of the shank seated on a lower seating surface of the receiver at the lower portion of the cavity.
 6. The bone screw assembly of claim 4, wherein the receiver is configured to restrict the upper end portion of the shank from passing from the cavity to a lower exterior of the receiver.
 7. The bone screw assembly of claim 1, wherein the hinged motion of the shank body is restricted to the single plane with respect to a central axis of the receiver.
 8. The bone screw assembly of claim 1, wherein the receiver is configured to be removable from the upper end portion of the shank after the shank is deployed into a vertebra. 